Agenda - Public Works Committee - 03/16/2021

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The sanitary sewer televising showed that the sanitary sewer system is generally in good condition and does not need any major repairs. However, one small crack was observed in the obvert (top) of a pipe segment near the of Unity and 140th Street. Staff considered the options for repairing the crack and recommend lining the pipe in the future instead of replacing the pipe as part of this project, which would require closing the street for several days to dig the pipe up and replace it. It is also significantly cheaper to line a pipe than to excavate the street and replace the pipe and a portion of the street in the process. Lining a pipe can also be completed without closing the street to traffic. The storm sewer televising showed that more than half of the storm sewer was plastic pipe, and that much of the smaller diameter plastic pipe needed to be replaced. In addition, several hundred feet of concrete storm sewer needed to be replaced. This cost was not accounted for in the CIP storm sewer cost estimates, which significantly increased project costs. In 2020, Business Park 95 was included in the Ground Penetrating Radar Pavement Evaluation performed by Braun Intertec. This data provides bituminous and aggregate base thickness information. The Ground Penetrating Radar (GPR) data is included in the street segment summary attached to this case. The Business Park 95 subdivision is a commercial subdivision with heavy truck traffic. During the fall of 2020, Staff took traffic counts with annual daily traffic (ADT) volumes of; 846 on Unity Street south of Bunker Lake Boulevard, and 2,245 on McKinley Street east of Sunfish Lake Boulevard. The City does not have a standard commercial pavement section, however, since these roads must be open during all seasons to heavy truck traffic, the streets are proposed to be reconstructed to a 9-ton design using MnDOT's design guidelines. Based upon pavement coring's, the existing pavement section meets a 9-ton design. The existing concrete curb and gutter is generally in good condition. The streets are proposed to be reconstructed using the full -depth reclamation process. This includes reclaiming the existing pavement and aggregate base section, removing the top 4-inches of reclaim material, then compacting the remaining 6-inches of material in place to serve as aggregate base. Then 4-inches of new bituminous pavement is proposed to be placed on top to effectively provide a 10-inch minimum pavement section, meeting a 9-ton design strength. The pavement on the east end of McKinley Street ends approximately 450-feet east of Radium Street, after which it becomes a gravel surface for approximately 75-feet before turning into a private driveway. This leaves no space within public right of way for snow plows or emergency vehicles to turn around. The plans include and alternate bid for extending the pavement on McKinley Street approximately 250-feet east, and constructing a paved cul-de-sac on the east end within existing right-of-way. The cul-de-sac extension is supported by the Public Works Department and Fire Department. This cul-de-sac extension would have the added benefit of providing better access to an existing trunk sanitary sewer line which exists in green space east of McKinley Street. Bidding the cul-de-sac extension as an alternate bid will allow the City Council to know the bid price before deciding whether to construct the cul-de-sac extension. Approximately 450-feet of the west end of McKinley Street is proposed to be left as is as this segment will be reconstructed with the Sunfish Lake Boulevard & BNSF Railway grade separation improvements, part of the Ramsey Gateway Highway 10 Improvements project. The construction limits on the west end of McKinley Street were designed to match the tie down location for the segment of McKinley Street to be reconstructed with the Ramsey Gateway Improvements to avoid throw away costs. Timeframe: Staff anticipates up to 15 minutes will be needed to present and discuss this case. Observations/Alternatives: